California law states that water suppliers must protect the public water supply from contamination by implementing a cross connection program. As part of that requirement, the Irvine Ranch Water District (IRWD) is required to periodically review customers' water systems to determine if they are in compliance with the code. These regulations apply only to IRWD commercial and industrial customers, or customers who use BOTH potable (drinking) water and recycled water.

The responsibility of implementing the various elements of an effective cross connection control program requires the full cooperation of water users, water suppliers, health agencies, and user supervisor. Each must carry his/her share of a coordinated cross connection control program in order to prevent contamination of the potable water supply.

What is a "Cross Connection"?
A cross connection is a potential connection between any part of a water system used to supply water for drinking purposes, and a connection to a source not approved as safe for human consumption. Under this condition, contamination of the drinking water system may occur by back-siphonage or back pressure. Back-siphonage is caused by negative or reduced pressure in the drinking supply system. Some of the causes of back-siphonage are undersized piping and water line repairs at a location lower than a service point. Back pressure occurs when a pressurized non-drinking water piping system is connected to a drinking water system operating at lower pressure. Some of the causes of back pressure are booster pumps supplying make-up water to industrial fluid piping systems from potable water systems and interconnection with other piping systems operating at high pressure.

Cross connection control and plumbing inspections on the premises of its customers are regulated and are handled through rules and regulations of IRWD and the health authority. From time to time, representatives of any health agency having jurisdiction and/or IRWD may conduct surveys of any premises where water service is provided by the District. On a daily basis the District conducts unannounced inspections of commercial and industrial sites. The purpose of such surveys is to determine if any actual or potential cross connections exist. The applicant owner or customer shall provide reasonable cooperation in facilitating such surveys. There are two types of surveys: the initial survey and the follow-up survey. An initial survey is performed on newly initiated customer's premises. IRWD is aware of new construction in its service area, and reviews the construction diagrams for water piping before a facility is built. The follow-up survey is important in commercial and industrial areas due to changes in water use among customers.

Back Flow Prevention Devices
The regulations allow only three types of backflow prevention assemblies to be used for abatement of cross connection hazards at a customer's service connection.

There are different types of backflow prevention devices required under each of these conditions. The type of device required will depend on the water use.

It is the duty of the water user on any premises on which backflow prevention devices exist to have competent inspections made at least once a year, or more often in those instances inspections indicate repeated failure. All testing shall be performed by a tester certified by the Orange County Health Care Agency. The District will notify the applicant, or owner, 30 days in advance when routine testing is needed and supply them with the necessary forms and a list of certified testers. A second 30-day notice shall be sent to each water user who does not have their backflow prevention device tested within the time allowed. At the end of 30 days, if no action is taken the District will send the user a certified letter giving the customer 10 days to test or repair the backflow device or water service will be terminated. The District may turn off the water until the device passes the test.

The District has developed an active cross connection control program with a cross connection control manager to administer the program. Any questions or notifications regarding these provisions or program should be directed to the manager at 453-5761.

Dual Systems
IRWD maintains dual distribution systems: one set of pipes to deliver potable drinking water, and a separate set of pipes to provide recycled water in non-residential dual plumbed buildings. Recycled water inside commercial or industrial buildings is primarily used for toilet and urinal flushing and for industrial processes. All recycled water piping is clearly identified so it is distinguishable from potable water piping. In addition to purple piping or mylar warning tape, a reduced pressure principle backflow assembly (RPPA) is installed on the domestic water line serving the building. Before occupancy is permitted, a thorough cross connection test and inspection of both the potable and recycled water systems is required. A shutdown test must be conducted prior to activating the recycled water.